Great list!
Short-eared owl at #432 and #458 a mistake?
That is a mistake indeed... So the final total should be 501.
Mammals
92. South-American grey fox
Birds
The following are all from the Falkland Islands, where we cleaned up all breeding birds, except a few waterbirds (which we saw afterwards in Chile/Argentina) and some seabirds...
413. Southern caracara
414. Striated caracara
415. Blackish cinclodes (Tussacbird)
416. Rock cormorant
417. Imperial cormorant
418. Rufous-chested dotterel
419. Crested duck
420. Black-throated finch
421. Southern giant petrel
422. Kelp goose
423. Upland goose
424. Ruddy-headed goose
425. Silvery grebe
426. Dark-faced ground tyrant
427. Brown-hooded gull
428. Dolphin gull
429. Kelp gull (ssp. austrinus)
430. Variable hawk
431. Long-tailed meadowlark
432. Short eared owl
433. Blackish oystercatcher
434. Magellanic oystercatcher
435. Gentoo penguin
436. King penguin
437. Magellanic penguin
438. Macaroni penguin
439. Southern rockhopper penguin
440. Yellow-billed pintail
441. Correndera pipit
442. Two-banded plover
443. White-rumped sandpiper
444. Sooty shearwater
445. Snowy sheathbill
446. Black-chinned siskin
447. Brown skua ("Falkland skua")
448. Magellanic snipe
449. Falkland steamer duck
450. Silver teal
451. Speckled teal
452. South-American tern
453. Austral thrush
454. Turkey vulture
455. Chilean wigeon
456. Cobb's wren
457. Sedge wren
458. Short-eared owl (ssp. sanfordi)
Additionally the Falklands also had some new subspecies of species already seen this year (tuidara for Barn owl, cassini for Peregrine falcon, rubida for Sanderling and falklandicus for Black-crowned night heron).
The rarest bird species of the Falklands was a barn swallow (ssp. erythrogaster) though, which is a vagrant to the islands, whereas all other species are more regular species to these amazing islands.
then I spent almost 3 weeks in the extreme south of Chile (and a small detour into Argentina) with the following additional species in 2017:
459. Austral blackbird
460. Black-chested buzzard eagle
461. Cordilleran canastero
462. Chimango caracara
463. Dark-bellied cinclodes
464. Bar-winged cinclodes
465. Andean condor
466. Red-gartered coot
467. White-winged coot
468. Neotropic cormorant
469. Fire-eyed diucon
470. Tawny-throated dotterel
471. Eared dove
472. Spectacled duck
473. Torrent duck
474. Scale-throated earthcreeper
475. White-crested elaenia
476. Chilean flamingo
477. Chilean flicker
478. Great grebe
479. White-tufted grebe
480. Ochre-naped tyrant
481. Cinereous harrier
482. Black-faced ibis
483. American kestrel
484. Southern lapwing
485. Common miner
486. Austral negrito
487. Austral parakeet
488. Rufous-tailed plantcutter
489. Thorn-tailed rayadito
490. Darwin's rhea
491. Grey-hooded sierra finch
492. Chilean skua
493. Rufous-collared sparrow
494. Chilean swallow
495. Black-necked swan
496. Coscoroba swan
497. Tufted tit-tyrant
498. White-throated treerunner
499. Chocolate-vented tyrant
500. Magellanic woodpecker
501. Striped woodpecker
502. Southern house wren
I uploaded a few pictures to the Falkland Islands gallery, as there won't be a travel thread:
Falkland Islands - Wildlife | ZooChat